ES2764074T3 - Hygienic disposable pants - Google Patents

Abstract

Disposable hygienic pants with a longitudinal direction and a transverse direction, comprising, in the longitudinal direction, a front part (2), an intermediate part (4) between the legs provided with two leg cuts, and a rear part (3) , the outer longitudinal edge portions (21, 22) of the front being connected, by longitudinal joining seams (7, 8), to the outer longitudinal edge portions (31, 32) of the rear portion (3) forming thereby a waist opening (9) that is delimited by the outer transverse edge portions (22, 33) of the front and the rear, and forming two leg openings (5, 6) that are delimited outward in the transverse direction through the inner end portions of the joining seams, in which the hygienic pants comprise an outer elastic liner (10) comprising an elastic laminate comprising an elastic film applied to a material nonwoven and an absorption unit (11) that extends in the longitudinal direction through at least part of the crotch part (4), in which the hygienic pants are characterized in that said joining seams (7, 8) are each reinforced by one or more pieces of reinforcing material (15, 16, 17, 18, 19, 20, 35) containing thermoplastic fibers, and in which said reinforcing material has been glued (25, 26 , 27, 28, 29, 30, 37) to inner surfaces of the front (21, 22) and / or the rear of the elastic outer lining (10) close to the joining seams (7, 8) in such a way that the reinforcing material extends into said joint seams (7, 8), and that the tensile strength of the joint seams, in a direction transverse to the joint seam and in said transverse direction, exceeds 5 N / 25.4 mm at least in the parts reinforced with said reinforcing material (15, 16, 17, 18, 19, 20, 35), and because the res Tensile strength of said liner in the transverse direction exceeds the tensile strength for reinforced joint seams.

Description

DESCRIPTION

Hygienic disposable pants

Technical field

The present invention relates to disposable sanitary pants, such as diaper pants.

Background

There is a great demand for the fit and comfort of sanitary pants such as diaper pants for children and compress pants for adults. Hygienic pants preferably have sufficient elasticity in the transverse direction (i.e., the horizontal direction when the pants are kept vertical) so that they are easy to take off and put on by the user, a family member or a caregiver. There is also a preference that they should be soft and textile-like. Hygienic pants, particularly for adult users, are preferably discreet and non-bulky, at least in areas outside the actual absorption unit. As they are disposable products, the cost is preferably minimized, in particular the costs of materials and manufacturing. For cost reasons, the included material layers are preferably as thin as possible. At the same time, quality and resistance requirements must be met.

Hygienic pants, such as diaper pants, preferably resist wear and tear during use. When put on, sanitary pants can experience significant stresses, for example pants stretch when pulled over the user's hips. In particular, the longitudinal joint seams connecting the front parts to the back parts of the garment on the sides of the pants are exposed to considerable stresses.

In traditional sanitary pants, the linings are made of double layers of non-woven fabric with elastic threads between them. At the side seams attached in this type of lining there are no less than four layers of a nonwoven fabric attached, in which the seams have not been forcibly torn or weakened in relation to the production of the lining, which can provide a seam strong enough bonding.

WO 03/047488 discloses an elastic laminate consisting of an elastic film applied between two layers of a non-woven fabric. During the production of the elastic laminate these layers of nonwoven fabric have been connected to the film, after which the laminate has been stretched until the seams in the layer of the nonwoven fabric have been broken. As a consequence, the elasticity of the laminate is largely the same as the elasticity of the elastic film. A disadvantage of this solution is that the joint seams on sanitary pants made with linings made from such laminates can have considerably less strength than the joint seams on traditional diaper pants.

Other examples of elastic laminates used in making sanitary pants are described in PCT applications WO 2005/122984 and WO 2005/122985. Contrary to the production method disclosed in WO 03/047488, the joints of at least one layer of a non-woven fabric have not been completely broken, instead the layer retains a certain residual strength. PCT applications WO 2005/122984 and WO 2005/122985 describe laminates in which elasticity has been combined with softness and puncture resistance. However, the bonded side seams of the hygienic pants made with laminates described in PCT applications WO 2005/122984 and WO 2005/122985 may be even weaker than the joint seams of traditional pants.

EP 0990 434 A2 discloses a disposable diaper panty with seams joined by a plurality of heat sealing areas.

Other disposable absorbent articles are described in document EP0875226, and in documents WO2006 / 093444 and WO2007 / 008128 under article 54 (3) of the CPE.

As can be seen from the above, many demands, some of them contradictory, have been placed on disposable toilet pants. Improvements in technique are still desired.

Compendium

What is described here are disposable hygienic pants, such as diaper pants. The pants can be described with reference to a longitudinal direction, which corresponds to the vertical when the pants are kept vertical, and to a transverse direction, which is a horizontal direction from side to side when the pants are kept vertical. The pants comprise in the longitudinal direction a front part, an intermediate part of the crotch provided with the cuts of leg openings, and a rear part, where the outer parts of the longitudinal edge of the front part are connected by seams of longitudinal attachment to the rear parts of the longitudinal edge of the rear part in order to form an opening in the waist delimited by the outer parts of the transverse edge of the front and the rear and forming two leg openings in the crotch part, where said leg openings are delimited in the transverse direction by inner parts end of the joint seams. Hygienic pants comprise an absorption unit that extends in the longitudinal direction through at least part of the crotch portion. Hygienic pants also comprise an outer lining that is made of an elasticized material comprising an elastic film applied to a layer of a non-woven fabric material or a layer of an elastic film applied between two layers of a non-woven fabric material .

Hygienic pants are characterized by comprising seam reinforcing pieces of a material comprising thermoplastic fibers, such as a bonded non-woven fabric material, adhesively glued proximate to each joint seam on at least one of said front part and / or said rear part, such that a part of a material joining reinforcement piece extends into each of said joining seams between said longitudinal edge parts of said front part and said rear part. The pieces of joint reinforcing material are adhesively bonded to the inner surface of the front and / or rear parts of the elastic outer liner, and more preferably the adhesive is located proximate to the joint seam so that it does not spread in the area of the seam of union. As used herein, close to the joint seam means close to the joint seam, for example at least within about 5 cm, preferably at least within about 3 cm, and most preferably at least in one location within about 1 cm of the union. Generally, it is preferred to place the adhesive within the joint seam and as close as practical at the joint seam site without spreading within the joint seam, but this does not exclude that the reinforcing material is also bonded by an adhesive that is less close to the joint seam, for example in the case of a piece of reinforcing material extending transversely across the front or back, the adhesive can be used continuously or at discrete points through the width of the reinforcing material. Additional pieces of the reinforcing material can be applied to spread at each joint with or without adhesive bonding.

Accordingly, in preferred embodiments the sanitary pants may be characterized in that the joint seams are each reinforced by at least one reinforcing strip containing thermoplastic fibers, in which the reinforcing strip has been glued to the front or the rear of the sanitary pants at least along said inner end parts, seen in the longitudinal direction of the sanitary pants, of the two edge parts and has been joined together with said parts of the longitudinal edge of the lining in order to forming said joint seams. The reinforcing strips are preferably composed of a melt blown or spun material of a non-woven fabric or the like. A reinforcing strip is at least wide enough in the transverse direction to accommodate being adhesively bonded near the joint, but not in the area of the joint. The reinforcing strip can cover the transverse width of the pants on the front and rear parts, such a strip can be adhesively glued to the front and / or rear parts, just as a strip can be adhesively glued to the front or rear part by using a adhesive at a location close to the joint, and the strip may also be adhesively bonded at points that are closest to the joint seam.

Hygienic pants are also characterized in that the tensile strength of the joint seams, in a transverse direction to the joint seam exceeds 5N / 25.4mm, more preferably the minimum tensile strength exceeds 10N / 25.4mm , or 12N / 25.4 mm and can be on average at least 15N / 25.4 mm or 20N / 25.4 mm in the parts reinforced with said strip of a non-woven fabric, where the resistance to breakage of the Lining in the transverse direction preferably exceeds the tensile strength of the reinforced joint seams.

According to an embodiment, a hygienic pants can be characterized in that the longitudinal edge parts of the front part and the rear part of the lining, at least along its end parts in the vicinity of the waist opening of the pants and / or in the vicinity of the leg opening, they have been provided with reinforcing strips. In one embodiment, the hygienic pants can be characterized in that a reinforcing strip is adhesively bonded to the lining next to the joint seams in each of said parts of the longitudinal edge of the front or the back, and where it is applied a reinforcing strip with or without adhesive on each part of the longitudinal edge of the other on the front or the rear, as a result of which the joint seams, at least in their reinforced areas, comprise two layers of said strips reinforcement of a non-woven fabric.

In some embodiments, the pants may be characterized in that, when the joint seam is performed, the front or the back is disposed towards an ultrasonic horn and the other of the front or the rear is disposed towards an anvil, and wherein the reinforcing strips of material are applied only to the inner surface of the front or back, preferably to the inner surface of the part where the ultrasonic horn contacts. In some embodiments where this arrangement is preferred, when the joint seam is performed, the ultrasonic horn is fixed with respect to the transverse direction of the pants and the anvil moves in the transverse direction of the pants. Alternatively, when the reinforced bond is weaker between the front and the reinforcing strip or between the rear and the reinforcing strip, the reinforcing strip is preferably adhesively glued proximate to the bonding seam on either the front or rear where the weakest side is.

In some embodiments, the pants may be characterized in that a reinforcing strip is comprised of a single strip that extends transversely through the sanitary pants. In some embodiments, the pants may be characterized in that, in the longitudinal direction of the sanitary pants, a strip extends only through said inner end portions of the two cross edge portions.

Also described is a method of forming a joint seam that is not part of the invention. The joint seam is formed between a first material and a second material, preferably elastic materials such as an elastic laminate. The method comprises adhesively adhering a reinforcing material comprising thermoplastic fibers to at least one of said first and second materials, close to the place of attachment, such that a part of said reinforcing material extends at the seam location. of union between said first and second materials. The adhesive can be placed in such a way that it is close to, but not in the area of, the joint seam. In which the joint seam is formed along a longitudinal direction between materials that move in a transverse direction by using a fixed ultrasonic horn and an anvil that moves or rotates in the transverse direction at a speed equivalent to that of the first and second materials, so that said first material is disposed towards the horn and the second material is disposed towards the anvil when the joint is being formed, the reinforcing material is adhesively adhered to at least the first material. Alternatively, when the reinforced bond seam is weaker between the first material and the reinforcing material, or between the second material and the reinforcing material, the reinforcing material is preferably adhesively bonded to any of the first or second materials that are on the weaker side.

Description of the figures

Figure 1 shows a schematic perspective view of an illustrative embodiment of sanitary pants as described herein.

Figure 2 shows a cross section along line II-II in Figure 1.

Figure 3 shows a schematic perspective view of another illustrative embodiment of sanitary pants as described herein.

Figure 4 shows a cross section along line IV-IV in Figure 3.

Figure 5 shows a schematic perspective view of another illustrative embodiment of sanitary pants as described herein.

Figure 6 shows a cross section along line VI-VI in Figure 5.

Figure 7 shows a schematic perspective view of another illustrative embodiment of sanitary pants as described herein.

Figure 8 shows a cross section along line VIII-VIII in Figure 7.

Figures 9-11 schematically show a method for measuring the joint strength of sanitary pants according to an embodiment of the present invention.

Figure 12 shows a stress / load diagram to illustrate the change in joint strength with an applied backing without adhesive as described here.

Figures 13-15 a method for making a joint seam between the layers of an elastic laminate that is not part of the present invention.

Detailed description of preferred embodiments

Elastic laminates have various desirable characteristics when used as elastic linings for sanitary pants. A laminate comprising an elastic film between two layers of a non-woven fabric can give the lining the desired elastic properties while the fibers in these layers of non-woven fabric give the lining a soft textile feel. The structure of the laminate is preferably configured so that the elastic stretching of the lining is not impeded by the layers of nonwoven fabric. However, the strength of the joint seams of sanitary pants that have linings of an elastic laminate can be negatively affected by the structure and composition of the laminate, in which the fiber seams have been partially or completely broken. In some lining materials of elastic laminates the fibers of the layers of a non-woven fabric have been more or less stretched to the point of rupture in the manufacture of the laminate. It has also been discovered that typical methods of making joint seams such as those used in sanitary pants can affect the strength of the joint seams in some ways surprisingly negative. In particular, it has been discovered that in a high speed production line using a fixed ultrasonic horn and an anvil that moves transversely to form a joint along a longitudinal direction, the joint can be significantly weaker, and that when bonding involves more than two layers the bonding between the layers on the horn side tends to be weaker. Without wishing to be bound by theory, it is believed that this phenomenon can be explained by the breakage of fibers in the material that moves transversely while in contact with the fixed horn.

By means of the methods described herein, the risk that the bonded side seams on the sanitary pants will break prematurely can be significantly reduced, so that the elastic layered materials can be used safely and economically to make improved sanitary pants.

Figure 1 shows sanitary pants in the shape of diaper pants 1 for incontinent children or adults. The diaper pants 1 have a front part 2, a rear part 3 and a part 4 of the crotch in which the leg openings 5, 6 are arranged. The diaper pants have a transverse direction, which in Figure 1 has been marked with X, and a longitudinal direction, which has been marked with Y. The outer parts 21 and 22 of the longitudinal edge of the front, seen in the transverse direction , are connected by connecting seams 7 and 8 to the outer parts 31 and 32 of the longitudinal edge of the rear part 3, seen in the transverse direction, in order to form a waist opening 9, which is delimited by the outer parts 23 and 33 of the transverse edge of the front and rear.

The sanitary pants include an outer lining 10. The liner 10 is elastic, and comprises an elastic laminate containing an elastic film applied between two layers of nonwoven fabric. Appropriate three-layer elastic laminates for this purpose are described in detail, for example in PCT applications WO 2005/122984 and WO 2005/122985. A suitable two-layer elastic laminate is described in PCT patent applications PCT / SE2006 / 000563 and PCT / SE2006 / 000564.

The laminate is elastic at least in the transverse direction of the diaper pants, that is, in the X direction in Figure 1. The elasticity in the X direction is preferably at least 30%, more preferably at least 50%, and most preferably at least 70%, measured according to the elasticity test described in the aforementioned patent applications.

The outer fiber layers in the laminate can provide softness and a textile feel. Examples of such materials are cast blown nonwoven fabrics and spunbond nonwoven fabrics. The weight of said fibrous layers is preferably between 10 and 35 g / m2, preferably between 12 and 30 g / m2, and particularly preferably between 15 and 25 g / m2. Examples of suitable fiber materials such as polyethylene and polypropylene are indicated in the aforementioned patent applications. The elastic film is conveniently perforated so that the lining is made permeable to air and steam. The grammage of the elastic film is conveniently between 10 and 120 g / m2, preferably between 20 and 60 g / m2. Suitable examples of materials and material combinations for the elastic film are indicated in the aforementioned patent applications WO 2005/122984 and WO 2005/122985.

The laminate in the liner 10 can be produced according to a modified version of the method disclosed in WO 03/047488. As has been described in said patent applications WO 2005/122984 and WO 2005/122985, the modification is that at least one of the layers of a non-elastic nonwoven fabric has been stretched with a maximum load so that a significant resistance is still present in at least one of the layers of the nonwoven fabric.

In other embodiments, materials such as those described in PCT patent applications PCT / SE2006 / 000563 and PCT / SE2006 / 000564 can be used to make the lining. The elastic panels described therein are formed by preparing a two-layer laminate comprising a non-elastic fibrous nonwoven fabric mesh and an elastic film. Suitable materials for such laminates are described therein. The two-layer laminate is activated by stretching it in at least one direction by 10200% to make the laminate elastic in at least that direction. In a trouser forming process, the stretched laminate may be laminated into another component mesh of the frame.

Alternatively, the liner laminate may also be comprised of an elastic laminate which has been produced entirely in accordance with that described in WO 03/047488.

The term "lining" used herein designates a frame that supports the pants and preferably elastically surrounds a trunk of the wearer, thereby supporting the pants in their entirety. In the illustrative embodiment shown in Figure 1 the lining is composed of a front part 2 and a rear part 3. The diaper pants according to Figure 1 have a crotch part 4 attached to the lining and in the shape of a unit Absorption 11. This absorption unit 11 has a liquid-impermeable outer sheet 12, a liquid-permeable inner sheet 13, and an absorption body 14 arranged between these sheets. The liquid-permeable sheet may, for example, be composed of a non-woven fabric, such as a yarn. The liquid impervious outer sheet 12 can, for example, be made of a thin plastic film, such as as a polyethylene or polypropylene film. The absorption body may, for example, be composed of cellulose pulp or absorbent foam, possibly in combination with a super absorbent material. Other suitable materials and material combinations for the liquid-impermeable sheet 12, the absorption body 14 and the liquid-permeable sheet 13 are disclosed in patent applications WO 2005/122984 and WO 2005/122985.

The sanitary pants described in WO 03/047488 and the sanitary pants described in patent publications WO 2005/122984 and WO 2005/122985 and patent application PCT / SE2006 / 000563 comprise elastic laminates with a suitable degree of elasticity. for use in sanitary pants. This has been partially or completely accomplished by breaking the fibers or bonds in at least one of the layers of a non-woven fabric surrounding the elastic films in the elastic laminate. A major disadvantage of nonwoven fabric seams in the laminate that has been partially or completely broken is that the tensile strength of the joint seams 7 and 8 is weakened compared to that of traditional diaper pants which They comprise four bonded non-woven fabric layers connected by means of the bond seams.

Bonded non-woven fabric layers herein designate non-woven fabrics that have not been forcibly torn or weakened during liner production, but instead maintain their tensile strength. In traditional diaper pants, the linings are made of double non-woven fabrics and elastic threads between them. In the joint seams, therefore, there are no less than four layers of bonded non-woven fabrics, thereby providing a sufficiently strong joint seam.

Hygienic pants are subject to considerable stress when being worn. The hygienic pants are stretched and the joint seams are exposed to considerable stresses. Especially the critical areas at the ends of the joint seams at the leg or waist openings.

In the embodiment according to Figure 1, the joint seams 7 and 8 have been reinforced with strips 15, 15 'and 16, 16' of a reinforcing material, the strips have been applied inside the lining to the along edge portions 21, 31 and 22, 32, as can be seen in Figure 2. Preferably, reinforcing strips 15 and 16 are adhesively bonded to back 3 at adhesive sites 25, 26 proximate the seams 7, 8 but not in the joint areas 7, 8, and the reinforcing strips 15 ', 16' are adhesively bonded to the front 2 at the adhesive sites 25 ', 26' next to the joints 7, 8 but not in junction areas 7, 8.

The reinforcing strips contain thermoplastic fibers, which, after joining the joint seams, reinforce the seam. Nonwoven fabric materials are preferred. For example, molten blown materials and spun materials are suitable reinforcing materials. However, other flexible and optionally extensible materials can be used, for example Yarn-Blown Melt-Yarn (SMS) laminates.

In alternative embodiments it may be sufficient to include only pieces 15, 16 or pieces 15 ', 16' at the rear or front of the pants. When the joints 7, 8 are formed into diaper pants that move in a transverse direction and that use a fixed ultrasonic horn and a transversely moving anvil it is preferable to include at least parts 5, 16 or 15 ', 16' glued to any of the front or rear parts facing the fixed horn when the joint is formed.

The reinforcing strips 15, 16 may, for example, be made of yarn and applied to the edge portions of the liner before they are joined together. As stated, the strips are preferably adhesively attached to the liner at the time the strips are applied. The reinforcing strips are preferably unstretched in application to the edge portions of the liner, thus the fiber bonds have not been weakened. When the edge portions are joined together the reinforcing strips can retain substantially all of their tensile strength, unlike the layers of fibers of elastic material in which the fiber bonds have been partially or totally broken.

In this way, the presence of the reinforcing strips at the joints can provide a reinforcement of the joint between the layers of the lining. In addition, by adhesive bonding the reinforcing strip to an inner surface of the liner material in an area close to the joint, the reinforcing strip can provide an unnecessary connection. If the bond formed between a portion of the elastic liner and a reinforcing strip fails as a result of weakened or broken fiber bonds in the elastic liner material, the adhesive that binds the reinforcing strip to the elastic lining can maintain the integrity of the sewing.

This is because the joint between the reinforcing strips and / or between a reinforcing strip and a lining part that is arranged towards an anvil that moves transversely with the sanitary pants as when a longitudinal ultrasonic joint seam is formed in The transverse edges of hygienic pants that move transversely tend to be stronger than the bond between two directly attached elastic liner sheets or an elastic liner sheet and a reinforcing strip that is disposed toward a fixed horn when a seam is formed Longitudinal ultrasonic joint at the transverse edges of the hygienic pants that move transversely.

As mentioned before, the stresses in the joint seams are considerable at the leg openings. In the embodiment shown in Figures 3 and 4, two reinforcing strips 17, 18 have been applied inside the lining through the sanitary pants and only through the inner end parts of the end parts of the lining, that is in the leg openings. The reinforcing strips 17, 18 are applied, one at the front and the other at the rear, before these parts have been joined together by means of the joint seams to form the lining. Preferably, the strips 17, 18 are adhesively glued to the rear and front parts 3, 2 by an adhesive 27, 28, which is applied at least proximal to the areas of the joints 7, 8, but not in the area where the union is formed. In Figures 3 and 4 the details have been provided with the same reference numbers corresponding to equivalent details in the illustrative embodiment in Figure 1.

Figures 5 and 6 show diaper pants in which only the portions of the lining edge in the immediate proximity of the leg openings have been reinforced with straps 19 and 20. In this embodiment, only one strap has been applied inside from front 2 of lining in leg opening. In an alternative not shown, the strips 19, 20 could be applied to the rear part 3. When the joint seams 7, 8 are formed in pants that move transversely using a fixed ultrasonic horn and an transversely moving anvil, it is preferable that the strips 19, 20 be adhesively glued to any of the front or back of the pants that is arranged towards the fixed horn. In Figures 5 and 6 the details corresponding to equivalent details in the embodiment according to Figures 1 and 2 have been provided with the same reference numbers.

In the embodiment according to Figure 5 the front and the back of the sanitary pants have been provided with the elastic bands 50 and 51 at the waist. These waist bands may conveniently be comprised of two layers of nonwoven fabric with various elastic threads applied between the layers of the nonwoven fabric. The waist bands are connected to the front and the rear by means of transverse joining joints of which one 53 has been indicated in Figure 5. When the front and the rear are joined together, the bands 50 and 51 of the waist are joined together by means of connecting seams 7 and 8. By means of the arrangement of the waist bands, the joint seams 7 and 8 are reinforced in the critical parts closest to the waist opening. In preferred embodiments the bonding of the layers of a non-woven fabric from the waist bands to the front and back of the lining is by means of a glue applied longitudinally and close to the joints 7, 8.

Figures 7 and 8 show diaper pants in which the reinforcing material 35 of a non-woven fabric is applied across the width of the back. The reinforcing material 35 preferably extends in the longitudinal direction over substantially the length of the joints 7, 8. A reinforcing mesh, such as a bonded nonwoven fabric mesh, laminated to the elastic panel can serve as a liner layer. and a reinforcing material, which is preferred when the liner is made by using a two-layer elastic laminate as described in patent applications PCT / SE2006 / 000563 and PCT / SE2006 / 000564. The reinforcing material is preferably adhesively bonded to a surface within the liner of the elastic laminate while the liner is in a transversely extended state, for example the panel of the elastic laminate may be extended in the transverse direction from approximately 10% to 200%, preferably from about 20% to about 125%, more preferably from about 50% to about 70% at the time the laminate and reinforcing material are bonded.

In the illustrated embodiment only one piece of reinforcing material has been applied within the rear part 3 of the lining. In an alternative not shown a single piece of the reinforcing material could be applied to the front part 2. The reinforcing strips that do not extend transversely across the width of the pants can be combined with the reinforcing material extending through the the width of the pants.

When the joint seams 7, 8 are formed into pants that move transversely using a fixed ultrasonic horn and an anvil that moves transversely or rotates, it is preferable that the reinforcing material 35 be adhesively glued to either the front or the back of the pants arranged towards the fixed horn. Alternatively, the pieces of the reinforcing material can be applied to the front and rear parts. In Figures 7 and 8 the details corresponding to the equivalent details in the embodiment according to Figures 1 and 2 have been provided with the same reference numbers.

In the illustrative embodiments described above the lining comprises front and rear parts and a separate part of the crotch which has been joined to the rest of the lining by means of a joint which has been indicated by 52 in the drawings. Thus, in the various exemplary embodiments, the liner may be made of one piece of an elastic laminate or of separate pieces of material with some pieces being substantially non-elastic. Diaper pants according to Figures 1-8 are illustrated with a crotch portion that is substantially non-elastic when stresses are applied.

Alternatively, the lining may also comprise the crotch part, that is to say so that the front part, the back part and the crotch part are in one piece of elastic material. The absorption unit is applied in this case to the part of the crotch inside the lining and connected to the latter, for example by means of a melted adhesive.

The tensile strength of the joint seams is measured according to the method (reference ASTM D 882) described in PCT patent application WO 2005/122984. Test samples are cut from the products, as shown in Figure 9, in areas that are reinforced with strips of nonwoven fabric. The width of the test samples will be 25.4 mm and the length, if possible, 50 mm longer than the distance between the jaws on the Instron 4301 tensile test instrument. Figures 10 and 11 show how the test samples Trial are fixed on the jaws.

To illustrate the effect of reinforcing joint seams by means of nonwoven fabric strips, Tables 1 and 2 show the results of the test of tensile strength measurements of a joint seam to connect two layers of an elastic laminate. with and without a reinforcement by non-woven fabric strips in various configurations. Table 1 provides a comparison of the results obtained without the backing strips versus when backing strips are used that are not adhesive-bonded to the liner of the elastic laminate. Table 2 shows the results that can be obtained by using reinforcing strips with and without adhesive bonding a reinforcing strip to the lining of the elastic laminate at a location near each joint, but not in the bonded area. Table 2 provides material comparisons of the higher basis weight reinforcement tape that is not adhesive bonded with a strip that is adhesive bonded.

The elastic laminate used in the test samples comprises a three-ply inner elastomeric PE-SEBS-PE film provided with holes and having a grammage of 36 g / m2 and two outer sheets of a spunbond nonwoven fabric, polypropylene, each one with a grammage of 22 g / m2. The laminate has been produced according to a modified version of the method described in WO 03/04788. According to the modified version, one spun sheet is applied to the film in a tacky state and thus bonded to the film, while the other spun sheet is adhesive laminated to the film by the use, for example, of an adhesive pressure sensitive (amount of adhesive 3 g / m2). The laminate is gradually stretched until the non-elastic spun sheets are stretched to a point less than full load extension in order to maintain some of its strength in the spun layers.

The grammages of the layers described above refer to the finished material after stretching. Before stretching, the weights of each of the layers were: inner film 40 g / m2, spun outer layer 25 g / m2, and adhesive layer 3 g / m2. Since it is difficult to measure the grammages of each of the layers after lamination and stretching, an approximation has been made based on the grammages of the layers before lamination and stretching. The total grammage of the laminate before stretching was 93 g / m2, and after stretching the grammage was 85 g / m2, which corresponds to a deformation of approximately 10%, it has been accepted that the deformation of each of the layers of fiber and the film is identical, ie approximately 10%.

The non-woven fabric backing strips were made from a yarn with a grammage of 20 g / m2 in Table 1 and 20 g / m2 or 30 g / m2. As will be seen in Table 1, the tensile strength of the reinforced joint was 10 N / 25.4 mm2 greater than that of the joint consisting of only two elastic laminates. As will be seen in Table 2, by gluing a reinforcing strip to the laminate at the rear, which in this example is the part that is arranged towards a fixed horn when the joint is formed using a transversely rotating anvil and a fixed horn, can provide additional reinforcement.

The particular values reflected in each table are naturally due to the particular construction of the layers and the grammage. The bonding method, bond strength fixation, amplitude fixation, and bonding pattern also affect resistance. Therefore, Table 1 should not be directly compared to Table 2. However, the results shown in Table 1 clearly illustrate that substantial joint seam reinforcement can be obtained with the help of reinforcing strips of nonwoven. The results shown in Table 2 show that substantial joint seam reinforcement can be obtained with the help of nonwoven fabric reinforcement strips. The results shown in Table 2 show that additional reinforcement of the joint seams can be obtained by adhesive bonding of at least one reinforcing strip. Figure 12 shows the stress-stress diagram of the test that corresponds to the results in Table 1.

TABLE 1. Tensile strength of the joints formed between elastic laminates with and without n l n i r f rz strips.

TABLE 2. Tensile strength of the reinforced bonds formed between elastic laminates with and

Practical tests have shown that the tensile strength of the joint seams in a direction transverse to the joint seam should be at least 5N / 25.4mm, preferably 7N / 25.4mm or more preferably at least 9 N / 25.4 mm to ensure reliable diaper pants. Through the examples of 25 or more sanitary pants, minimum side seam strengths of at least 10N / 25.4mm are preferred, or at least 12N / 25.4mm are most preferred, while average tensile strengths of at least 15 N / 25.4 mm are preferred.

Hygienic pants when worn should be capable of being easily opened at the joint seams in order to make them easier to remove. To obtain reliable operation in this regard, it is desirable that the liner breaking strength in the transverse direction exceed the tensile strength of the reinforced joint seams so that the hygienic pants, when removed, do not fall apart. uncontrollably and instead tear at the seams. The fact that seam reinforcements can be varied by choosing a non-woven fabric, the number of layers and the weight of the reinforcing strips offers a new possibility to vary the strength of the joint seam. This resistance can also be varied by choosing the type of connection and the connection pattern.

Figures 13-15 illustrate a method of making joint seam that is not part of the invention. Such a method makes an ultrasonically or thermally bonded reinforced bond seam when the reinforcing material is adhesively bonded to the elastic laminate liner material proximal to the site of a bond between two layers of the elastic laminate material. In Figure 13, the material 105, 106 of the elastic laminate moves transversely in direction 111 underneath a fixed ultrasonic horn 101. The anvil 102 supporting the bonding patterns 104 is bonded to the surface of the roller 103 moving in direction 113. The reinforcing nonwoven material 107 is attached to the inner surface of the elastic laminate 105, which is disposed towards the fixed horn, by the adhesive glue 108. The glue 108 could extend the total length of the material of reinforcement 107, but it is preferable that the glue 108 is located close to, but not where the joint is formed. After the compression joints of the laminates are formed between the horn 101 and the bonding patterns 104, the bonded material is cut at line 110 to form a seam 112 as illustrated in Figure 14. In practical experience the bonding 112 tends to be stronger on the anvil side. By using this method any weakness at junction 112 on the horn side is reinforced by the use of glue 108 for bonding backing material 107 to elastic laminate 105 on the horn side. Figure 15 illustrates a seam formed including a nonwoven fabric backing material 107 'in the elastic laminate 106 on the anvil side, which can be applied with or without glue 108'.

The sanitary pants described herein are not limited to the illustrative embodiments described above. Rather, a number of modifications are possible within the scope of the appended patent claims.

An elasticized liner need not be made of an elastic laminate throughout the entire front and the entire rear, and instead the front and / or rear parts can be made of a non-elastic material. It is preferred that the sanitary pants are sufficiently elastic so that the pants can be easily put on and taken off. For example, it may be sufficient that the back is made of an elastic laminate and that the rest of the toilet pants are not elastic.

Alternatively, the hygienic pants described herein may have elastic-layered linings only on the lateral parts of the front and the rear, and on the other hand have non-elastic central parts along the front, the Back and crotch lining that exceeds the tensile strength of reinforced joint seams.

Claims (19)

Disposable hygienic pants with a longitudinal direction and a transverse direction, comprising, in the longitudinal direction, a front part (2), an intermediate part (4) between the legs provided with two leg cuts, and a rear part ( 3), the longitudinal edge outer parts (21, 22) of the front part being connected, by means of longitudinal joint seams (7, 8), to the longitudinal edge outer parts (31, 32) of the rear part (3 ) thereby forming a waist opening (9) which is delimited by the outer transverse edge portions (22, 33) of the front and rear, and forming two leg openings (5, 6) which are delimited outward in the transverse direction through the inner end portions of the joint seams, wherein the sanitary pants comprise an outer elastic lining (10) comprising an elastic laminate comprising an elastic film applied to a mater Non-woven fabric and an absorption unit (11) that extends in the longitudinal direction through at least part of the crotch part (4), in which the sanitary pants are characterized in that said joint seams (7, 8 ) are each reinforced by one or more pieces of reinforcing material (15, 16, 17, 18, 19, 20, 35) containing thermoplastic fibers, and in which said reinforcing material has been glued by adhesive (25, 26, 27, 28, 29, 30, 37) to inner surfaces of the front part (21, 22) and / or the back of the elastic outer lining (10) next to the joint seams (7, 8) such such that the reinforcing material extends into said joint seams (7, 8), and because the tensile strength of the joint seams, in a direction transverse to the joint seam and in said cross direction, exceeds 5 N / 25.4 mm at least in the parts reinforced with said reinforcing material (15, 16, 17, 18, 19, 20, 35), and because the Tear resistance of said liner in the transverse direction exceeds the tensile strength for reinforced joint seams. 2. Hygienic pants according to claim 1, wherein the lining comprises an elastic laminate comprising an elastic film applied between two non-woven layers. Hygienic pants according to claims 1 or 2, in which the reinforcing material is glued together which is applied close to, but extending into, the area of the joint seam. Hygienic pants according to any one of claims 1 to 3, wherein said reinforcing material is a non-woven strip. Hygienic pants according to any one of claims 1 to 4, characterized in that said reinforcing material (15, 16, 18, 35) is adhesively bonded to at least the longitudinal edge parts of the rear portion of the lining. Hygienic pants according to any one of claims 1 to 4, characterized in that said reinforcing material (15, 16, 35) extends over the entire longitudinal length of the longitudinal edge parts. Hygienic pants according to any one of claims 1 to 4, characterized in that each joint seam (7, 8) is reinforced by a single piece of reinforcing material (15, 16, 17, 18, 19, 20, 35). Hygienic pants according to any one of claims 1 to 4, characterized in that the reinforcing material is adhesively bonded to the lining next to the joint seams in each of said longitudinal edge parts of either the front part or the back and that reinforcing material is applied with or without adhesive to each longitudinal edge part of the other of the front or the back, as a result of which the joint seams, at least in their reinforced areas, comprise two layers of said nonwoven reinforcing strips. 9. Hygienic pants according to any one of claims 1 to 4, characterized in that said reinforcing material is a single piece of reinforcing material that extends transversely through the hygienic pants. Hygienic pants according to claim 9, characterized in that, in the longitudinal direction of the hygienic pants, said single piece of reinforcing material extends only through the inner end parts of the two edge parts. 11. Hygienic pants according to claim 9, characterized in that, in the longitudinal direction of the hygienic pants, said single piece of reinforcing material extends through substantially all of the two edge parts. Hygienic pants according to any of the preceding claims, characterized in that said tensile strength through the joint seams (7, 8) in the reinforced parts exceeds 10 N / 25.4 mm. Hygienic pants according to any of the preceding claims, characterized in that said tensile strength through the joint seams (7, 8) in the reinforced parts exceeds 12 N / 25.4 mm. Hygienic pants according to any of the preceding claims, characterized in that said tensile strength through the joint seams (7, 8) in the reinforced parts exceeds 15 N / 25.4 mm. Hygienic pants according to any of the preceding claims, characterized in that said tensile strength through the joint seams (7, 8) in the reinforced parts exceeds 20 N / 25.4 mm. Hygienic pants according to any of the preceding claims, characterized in that, when the joint seam is made, either the front or the rear part is arranged towards an ultrasonic leather and the other of the front or rear part is arranged towards an anvil and in which pieces of reinforcing material stick to the inner surface of the part with which the ultrasonic horn contacts. Hygienic pants according to claim 16, in which pieces of reinforcing material stick only to the inner surface of the part with which the ultrasonic horn contacts. Hygienic pants according to claim 16 or claim 17, wherein, when the joint seam is being made, the ultrasonic horn is stationary with respect to the transverse direction of the pants and the anvil and pants move in the transverse direction of the pants. Hygienic pants according to any of claims 1 to 15, characterized in that the bond strength at said bond seams between either the front or the back and the reinforcing material is weaker than between the other of the front or rear portion, and in which the reinforcing material is adhesively bonded to the inner surface of any of the front or rear part that is on the weaker side.